Re: Cleaning Out XJ6 Fuel Tank Rust

In alt.autos.jaguar Abandoned Trolley <[email protected]> wrote:
> On 16/05/2026 02:32, OmberJag wrote:
>> I've got one of the rusty, gunky, fuel tanks out of my 1983 SIII
>> XJ6 that I'm trying to get back on the road. The car runs from the
>> other tank, but the pre-pump filter I fitted blocks up with rust
>> after a few minutes running, so I've got to to clean that tank
>> later as well. There aren't any businesses advertising fuel tank
>> repairs anywhere nearby that I can find, so cleaning them will need
>> to be a DIY job.
>> 
>> For removing the rust I can get some Sulfamic Acid for free (mixed
>> with Sodium Bisulfate). Phosphoric Acid seems more commonly used,
>> but Sulfamic Acid manufacturer websites say it works for rust
>> removal too (10-20% concentration). First I'll spin the tank on a
>> cement mixer with a chain inside to break off the big flakes of
>> rust, of which there look to be plenty.
> 
> If the flakes of rust are THAT big then its a surprise that the tank 
> doesnt leak

After the rust is removed, I'm worried it might. I've poked around
suspicious spots on the outside and it seems OK, but apparantly you
can get tiny pin-holes that are otherwise plugged up by the rust.

Or the gunk. I spent some hours today painfully trying to scrape
out the thick sticky black gunk that I thought I'd already drained
out after softening it with laquer thinners, but there was plenty
left disguised as metal by a layer of rust dust. The car was
sitting for unknown years and it must have distilled from the old
petrol. At least it does seem to have protected the tank surface
underneath in places where it pooled, but it glues the insides of
fuel pumps together too.

After more research I think I'll go for the washing soda and
battery charger "electrolytic" rust removal method. The acid would
eat away some of the metal too, which might leave a surface more
prone to rusting again. Or so I gather...

-- 
OmberJag's Jags:
1990 4L Jaguar XJ40
1986 3.6L Jaguar XJ40 (parts car)
1983 4.2L Jaguar XJ6 SIII